Answer: -1, 4, 21, 56.
Step-by-step explanation: The first 4 terms of the sequence defined by an = n^3 - 2n are as follows :
1. To find the first term, substitute n = 1 into the equation : a1 = (1)^3 - 2 (1)
1 - 2
-1
2. For the second term, substitute n = 2 : a2 = (2)^3 - 2 (2)
8 - 4
4
3. For the third term, substitute n = 3 : a3 = (3)^3 - 2 (3)
27 - 6
21
4. For the fourth term, substitute n = 4 : a4 = (4)^3 - 2 (4)
64 - 8
56
So as a result, the first 4 terms of the sequence are : -1, 4, 21, 56.